Muscular echinococcosis accounts for 0.5% to 5.4% of all hydatid disease ca
ses, with very little data on the incidence of muscular echinococcosis of t
he head and neck. We report a unique case of primary echinococcosis of the
right sternocleidomastoid muscle in a 56-year-old man. Preoperative assessm
ent by ultrasound and fine needle aspiration did not point to echinococcosi
s. We suspected the right diagnosis intraoperatively and confirmed it posto
peratively by pathohistology and serologic tests. Echinococcosis of the liv
er and the lungs was also excluded postoperatively. Combination of operativ
e treatment and postoperative albendazole herapy in two 28-day cycles one m
onth apart resulted in complete regression of the disease. Echinococcosis s
hould be considered as differential diagnosis of a multicystic mass in neck
, particularly if it is of longstanding duration. Serologic tests for echin
ococcosis should be included in differential diagnostic procedures for each
multicystic formation on the neck, especially in endemic areas.